Buggy code:
public final < C extends Page > CharSequence urlFor ( final Class < C > pageClass , final PageParameters parameters ) { } public final CharSequence urlFor ( final Behavior behaviour , final RequestListenerInterface listener ) { } public final CharSequence urlFor ( final IRequestHandler requestHandler ) { } public final CharSequence urlFor ( final RequestListenerInterface listener ) { } public final CharSequence urlFor ( final ResourceReference resourceReference , PageParameters parameters ) { } public final < R > R visitParents ( final Class < ? > c , final IVisitor < Component , R > visitor ) { } public final void warn ( final Serializable message ) { } private void notifyBehaviorsComponentBeforeRender ( ) { } private void notifyBehaviorsComponentRendered ( ) { } protected final void addStateChange ( ) { } protected final void checkComponentTag ( final ComponentTag tag , final String name ) { } protected final void checkComponentTagAttribute ( final ComponentTag tag , final String key , final String value ) { } protected void checkHierarchyChange ( final Component component ) { } protected void detachModel ( ) { } protected final String exceptionMessage ( final String message ) { } protected final MarkupStream findMarkupStream ( ) { } protected final Page findPage ( ) { } public < M extends Behavior > List < M > getBehaviors ( Class < M > type ) { } protected final boolean getFlag ( final int flag ) { } protected final boolean getRequestFlag ( final short flag ) { } protected final IModel < ? > getInnermostModel ( final IModel < ? > model ) { } public IModelComparator getModelComparator ( ) { } protected boolean getStatelessHint ( ) { } protected IModel < ? > initModel ( ) { } protected void internalOnModelChanged ( ) { } protected boolean isBehaviorAccepted ( final Behavior behavior ) { } protected final boolean isIgnoreAttributeModifier ( ) { } protected MarkupStream locateMarkupStream ( ) { } protected void onAfterRender ( ) { } protected void onBeforeRender ( ) { } protected void onComponentTag ( final ComponentTag tag ) { } public void onComponentTagBody ( final MarkupStream markupStream , final ComponentTag openTag ) { } protected void onDetach ( ) { } protected void onRemove ( ) { } protected void onModelChanged ( ) { } protected void onModelChanging ( ) { } protected abstract void onRender ( ) { } protected final void renderComponentTag ( ComponentTag tag ) { if ( needToRenderTag ( tag ) ) { List < ? extends Behavior > behaviors = getBehaviors ( ) ; if ( ( ( ( behaviors != null ) && ( ! ( behaviors . isEmpty ( ) ) ) ) && ( ! ( tag . isClose ( ) ) ) ) && ( ( isIgnoreAttributeModifier ( ) ) == false ) ) { tag = tag . mutable ( ) ; for ( Behavior behavior : behaviors ) { if ( isBehaviorAccepted ( behavior ) ) { behavior . onComponentTag ( this , tag ) ; } } } if ( tag . hasBehaviors ( ) ) { Iterator < ? extends Behavior > tagBehaviors = tag . getBehaviors ( ) ; while ( tagBehaviors . hasNext ( ) ) { final Behavior behavior = tagBehaviors . next ( ) ; if ( behavior . isEnabled ( this ) ) { behavior . onComponentTag ( this , tag ) ; } behavior . detach ( this ) ; } } if ( ( ( tag instanceof WicketTag ) && ( ! ( tag . isClose ( ) ) ) ) && ( ! ( getFlag ( Component . FLAG_IGNORE_ATTRIBUTE_MODIFIER ) ) ) ) { if ( getFlag ( Component . FLAG_OUTPUT_MARKUP_ID ) ) { Component . log . warn ( String . format ( ( "Markup<seq2seq4repair_space>id<seq2seq4repair_space>set<seq2seq4repair_space>on<seq2seq4repair_space>a<seq2seq4repair_space>component<seq2seq4repair_space>that<seq2seq4repair_space>is<seq2seq4repair_space>usually<seq2seq4repair_space>not<seq2seq4repair_space>rendered<seq2seq4repair_space>into<seq2seq4repair_space>markup.<seq2seq4repair_space>" + "Markup<seq2seq4repair_space>id:<seq2seq4repair_space>%s,<seq2seq4repair_space>component<seq2seq4repair_space>id:<seq2seq4repair_space>%s,<seq2seq4repair_space>component<seq2seq4repair_space>tag:<seq2seq4repair_space>%s." ) , getMarkupId ( ) , getId ( ) , tag . getName ( ) ) ) ; } if ( getFlag ( Component . FLAG_PLACEHOLDER ) ) { Component . log . warn ( String . format ( ( "Placeholder<seq2seq4repair_space>tag<seq2seq4repair_space>set<seq2seq4repair_space>on<seq2seq4repair_space>a<seq2seq4repair_space>component<seq2seq4repair_space>that<seq2seq4repair_space>is<seq2seq4repair_space>usually<seq2seq4repair_space>not<seq2seq4repair_space>rendered<seq2seq4repair_space>into<seq2seq4repair_space>markup.<seq2seq4repair_space>" + "Component<seq2seq4repair_space>id:<seq2seq4repair_space>%s,<seq2seq4repair_space>component<seq2seq4repair_space>tag:<seq2seq4repair_space>%s." ) , getId ( ) , tag . getName ( ) ) ) ; } } <START_BUG> tag . writeOutput ( getResponse ( ) , ( ! ( needToRenderTag ( null ) ) ) , getMarkup ( ) . getMarkupResourceStream ( ) . getWicketNamespace ( ) , getEscapeModelStrings ( ) ) ; <END_BUG> } } protected final void replaceComponentTagBody ( final MarkupStream markupStream , final ComponentTag tag , final CharSequence body ) { } protected final void setAuto ( final boolean auto ) { } protected final void setFlag ( final int flag , final boolean set ) { } protected final void setRequestFlag ( final short flag , final boolean set ) { } protected final Component setIgnoreAttributeModifier ( final boolean ignore ) { } protected final < V > IModel < V > wrap ( final IModel < V > model ) { } void detachChildren ( ) { } void removeChildren ( ) { } public Component get ( final String path ) { } final boolean hasMarkupIdMetaData ( ) { } void internalMarkRendering ( boolean setRenderingFlag ) { } public final boolean isAuto ( ) { } boolean isPreparedForRender ( ) { } protected void onAfterRenderChildren ( ) { } void onBeforeRenderChildren ( ) { } final void renderClosingComponentTag ( final MarkupStream markupStream , final ComponentTag openTag , final boolean renderBodyOnly ) { } final void setId ( final String id ) { } public final void setParent ( final MarkupContainer parent ) { } final void setRenderAllowed ( boolean renderAllowed ) { } void setRenderAllowed ( ) { } public final Component setVisibilityAllowed ( boolean allowed ) { } public final boolean isVisibilityAllowed ( ) { } public final boolean determineVisibility ( ) { } public final boolean isEnabledInHierarchy ( ) { } public final boolean canCallListenerInterface ( ) { } public void renderHead ( IHeaderResponse response ) { }

Fix:
tag . writeOutput ( getResponse ( ) , ( ! ( needToRenderTag ( null ) ) ) , getMarkup ( ) . getMarkupResourceStream ( ) . getWicketNamespace ( ) ) ;